Calcium lignosulfonate is used as a non-traditional stabilizer for clay and silty soils in unpaved roads, haul roads and earthworks. This page covers that geotechnical use. For clay used in ceramics, see calcium lignosulfonate for ceramics.
How it acts on clay soil
Lignosulfonate adsorbs on clay particles and binds them together as the soil dries. In the original description on this page this was called its dispersant, binding and chelating action. In practice it can improve the dry strength of compacted soil, reduce dust and surface erosion, and make compaction easier. Its main limitation is that the binder is water-soluble, so the improvement can be reduced when the soil is soaked for long periods.
What the evidence shows
Published laboratory studies on expansive clays, red clays and loess report changes in swelling, unconfined compressive strength and erosion resistance when lignosulfonate is added, sometimes together with cement or lime. Independent evaluations of non-traditional stabilizers, for example the US Army Engineer Research and Development Center study by Tingle and Santoni (Transportation Research Record 1819, 2003), found that results depend strongly on the soil type, the additive and the moisture condition. Treat published percentages as examples for that soil, not as design values for another site.
Typical applications
| Application | Purpose | What to test |
|---|---|---|
| Unpaved and haul roads on clayey or silty soil | Surface binding, dust and erosion control | Dry and soaked strength; field performance after rain |
| Road base and subgrade preparation | Easier compaction and higher dry strength | Proctor compaction, unconfined compressive strength |
| Slopes and embankments | Surface erosion reduction | Erosion and rainfall tests on the actual soil |
| Construction sites | Dust control on exposed clay | Dust and surface condition during works |
Laboratory and field qualification
- Classify the soil: grading, Atterberg limits, clay mineralogy if expansive behaviour matters.
- Run compaction tests with and without the additive.
- Test unconfined compressive strength in both dry and soaked condition at several additions.
- For expansive clay, measure free swell and swelling pressure.
- Build a field test section and monitor it through at least one wet period.
Grades and documents
For soil and road work we supply the calcium lignosulfonate dust control grade (powder, GAC-CaLS-DC: lignosulfonate content 55% min, dry matter 95% min) and the dust control liquid (45 – 55% solids), as well as the standard grades on the calcium lignosulfonate product page. Each grade has a TDS and MSDS; every shipment has a batch COA.
Agricultural use of calcium lignosulfonate on farm soils is a different subject; for agricultural grades see ChinaLignin.
Frequently Asked Questions
Can calcium lignosulfonate stabilize clay soil?
It can improve dry strength, compaction and erosion resistance of some clay and silty soils, but the binder is water-soluble and results vary by soil. Confirm with dry and soaked strength tests on the actual soil.
How much calcium lignosulfonate is added to clay soil?
There is no universal rate. Published studies use different soils and additions; set the rate with compaction and strength tests and a field test section.
What are the main uses of calcium lignosulfonate?
Industrial uses include concrete water reduction, binding of mineral and coal fines, ceramics, dust control, soil stabilization and drilling fluids. See the calcium lignosulfonate product page for grades.
Send soil data and project details to info@greenagrochem.com for a trial sample.
